import datetime
from decimal import Decimal


class DjangoUnicodeDecodeError(UnicodeDecodeError):
    def __init__(self, obj, *args):
        self.obj = obj
        super().__init__(*args)

    def __str__(self):
        return "%s. You passed in %r (%s)" % (super().__str__(), self.obj, type(self.obj))


_PROTECTED_TYPES = (
    type(None),
    int,
    float,
    Decimal,
    datetime.datetime,
    datetime.date,
    datetime.time,
)


def is_protected_type(obj):
    """
    Determine if the object instance is of a protected type.

    Objects of protected types are preserved as-is when passed to force_str(strings_only=True).
    """

    return isinstance(obj, _PROTECTED_TYPES)


def force_str(
    s,
    encoding: str = "utf-8",
    strings_only: bool = False,
    errors: str = "strict",
) -> str:
    """
    Similar to smart_str(), except that lazy instances are resolved to strings, rather than kept as lazy objects.

    If strings_only is True, don't convert (some) non-string-like objects.
    """

    # Handle the common case first for performance reasons.
    if issubclass(type(s), str):
        return s

    if (
        strings_only
        and is_protected_type(s)
    ):
        return s

    try:
        if isinstance(s, bytes):
            s = str(s, encoding, errors)

        else:
            s = str(s)

    except UnicodeDecodeError as e:
        raise DjangoUnicodeDecodeError(s, *e.args)

    return s
